[gtk+] GdkDevice: Fix an inverted assertion

[Matthias Clasen <matthiasc src gnome org>]

commit 116b5e560f91a4a145606454739d74b591bafb94
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jun 20 07:46:04 2012 -0400

    GdkDevice: Fix an inverted assertion
    
    gdk_device_list_slave_devices only makes sense to call on master
    devices, yet its g_return_if_fail check made it reject such devices.
    
    Pointed out by monty.

 gdk/gdkdevice.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdkdevice.c b/gdk/gdkdevice.c
index 0abfffe..3147d9e 100644
--- a/gdk/gdkdevice.c
+++ b/gdk/gdkdevice.c
@@ -939,7 +939,7 @@ GList *
 gdk_device_list_slave_devices (GdkDevice *device)
 {
   g_return_val_if_fail (GDK_IS_DEVICE (device), NULL);
-  g_return_val_if_fail (gdk_device_get_device_type (device) != GDK_DEVICE_TYPE_MASTER, NULL);
+  g_return_val_if_fail (gdk_device_get_device_type (device) == GDK_DEVICE_TYPE_MASTER, NULL);
 
   return g_list_copy (device->slaves);
 }